In recent years, technical development in electronic device-related fields has been remarkable, and in particular, the improvement of speed in personal computers has been making extraordinary technical advancements. Japanese Unexamined Patent Publication No. 2001-143798 describes, concerning a connector standard (device bay) used for connecting electrically to personal computer peripheral devices, a connector wherein the portions connecting to a board of the leg portions of two levels of electrical contact rows are capable of being grounded along a straight line on a flat plane, and wherein a plurality of electric connector rows are housed while minimizing the size of the connector.
In the two level type electric contact array disclosed in the aforementioned patent publication, the electric contacts of the lower level of the array are signal lines, and each of the electric contacts of the upper level are bus type electric connectors connected by a conductor.
However, as the speed of signal transfer increases, connector standards are also changing. Currently, ATA interfaces are utilized, focused on internal hard disks, for which high speed signal transfer is required, and in the future, it is expected that a serial ATA standard having the objective of replacing the conventional parallel interface with a high-speed serial interface in order to handle the speed increase of interfaces, as well as an increase in hard disk capacity due to a rapid improvement in the recording density of hard disks.
Further, as the interfaces in personal computers increase, many signal lines and grounding lines will be needed. As one method of solving this problem, it is possible to achieve this by stacking rows of the aforementioned signal lines or grounding lines in multiple levels, but for the required signal transfer speeds of several hundred megabytes per second, due to differences in the length of the conductor portion that arises due to the differing levels of the aforementioned rows, a large error arises in the impedance characteristic of the upper level in comparison to the lower level near the board, so the transfer characteristic of the signal becomes non-uniform. As a result, a misalignment of the phase of the transferred signal arises, and the reliability of signal transfer is reduced.
In order to overcome the aforementioned problems, it was hoped for that a connector would be provided that matches the impedance difference arising from the difference in conductor lengths due to the differing levels of the electric contact rows. The desired connector must house a plurality of levels of electric contact rows.